note version added and deprecated for bytes_value/value on DNSName (#3833)

diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index c2ff0ff..ea74846 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -1244,10 +1244,14 @@
 
     .. attribute:: bytes_value
 
+        .. versionadded:: 2.1
+
         :type: bytes
 
     .. attribute:: value
 
+        .. deprecated:: 2.1
+
         Deprecated accessor for the idna-decoded value of :attr:`bytes_value`
 
         :type: :term:`text`